JP2008127199A - Transfer paper curl remover and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer paper curl remover capable of carrying transfer paper after correcting the curl in the proper direction on the downstream side of a carrying passage, and capable of carrying the transfer paper in the proper direction on the downstream side of the carrying passage even if correction force of the curl is increased, and an image forming device. <P>SOLUTION: This image forming device has a pair of rollers mutually oppositely arranged in a pressure contact state and composed of a hard roller 32 and an elastic roller 33 different in hardness, a support shaft 34 and a guide groove 35 displaceably supporting the elastic roller 33 as one of the pair of rollers on the periphery of the hard roller 32 as the other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transfer paper curl removing apparatus and an image forming apparatus for removing curl of a transfer paper after image fixing.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine functionally equipped with these, after an unfixed toner image is formed on the surface of a transfer sheet by an image forming unit, It is well known that the unfixed toner image is melted and fixed on the surface of the transfer paper by the above method.

  Further, in such an image forming apparatus, as the transfer sheet is heated in the fixing unit, the temperature difference between the transfer sheet on the heating side (transfer sheet front surface) and the pressure side (transfer sheet rear surface side) of the fixing unit. Or the like, warping (curl) may occur at both ends along the transfer paper conveyance direction.

  For example, the curl generated on the transfer paper causes a problem that the transfer paper is difficult to be aligned when stapled by a post-processing device (finisher) installed adjacent to the image forming apparatus main body.

  In view of this, there has been considered a transfer paper curl removing device that cancels curl by generating curl in a direction opposite to curl generated after fixing (see, for example, Patent Document 1).

  FIG. 6 shows an example of such a transfer paper curl removing device, in which a pair of rollers 40 is arranged on the downstream side in the transport direction from the fixing unit (not shown).

  The roller pair 40 is disposed, for example, immediately before (on the upstream side) the transfer paper discharge port 42 of the image forming apparatus main body 41, and the transfer paper supply port of the post-processing device 43 disposed adjacent to the image forming apparatus main body 41. The transfer paper is conveyed to 44 while removing the curl.

  At this time, in the roller pair 40, a hard roller 45 made of a relatively hard material and an elastic roller 46 made of a relatively soft material are arranged in pressure contact with each other, and the surface of one hard roller 45 is the other surface. The elastic roller 46 is in a state of being bitten into the surface.

  As a result, the transfer paper whose end is curled downward in the figure is conveyed to the downstream side (transfer paper supply port 44 side) while receiving pressure that curls the end in the upward direction in the figure.

At this time, since the curl is extremely generated as the transfer paper is thicker, the curling correction force is changed by increasing the pressing force (biting amount) of the hard roller 45 against the elastic roller 46.
Japanese Unexamined Patent Publication No. 01-053979

  However, in the transfer paper curl removal apparatus configured as described above, even if the curl of the transfer paper that has passed through the roller pair 40 is finally removed, as shown by the chain line in FIG. The transfer paper transport direction accompanying the biting of the hard roller 45 with respect to 46 is transported upward in the figure with respect to the appropriate direction, and the transfer paper strikes the transfer paper discharge port 42 and the transfer paper supply port 44 to transfer the transfer paper. There was a problem of becoming a cause of jamming.

  In addition, there has been a problem that such a contact of the transfer paper is more easily generated by increasing the pressing force (biting amount) of the hard roller 45 against the elastic roller 46.

  Therefore, according to the present invention, the transfer paper after correcting the curl can be conveyed in an appropriate direction on the downstream side of the conveyance path, and even if the curling correction force is increased, the transfer paper is conveyed in an appropriate direction on the downstream side of the conveyance path. Another object of the present invention is to provide a transfer paper decurling apparatus and an image forming apparatus that can perform the above process.

  The transfer paper curl removing apparatus and the image forming apparatus according to the present invention support a pair of roller pairs that are opposed to each other and have different hardnesses in a press-contact state, and support at least one of the pair of roller pairs displaceably on the other circumference. And a guide portion.

  At this time, the guide portion is an arcuate guide groove based on a center coaxial with the other rotation center of the pair of roller pairs, or one of the pair of roller pairs approaches or separates from the other. As described above, it is preferable to provide an arcuate guide groove with the center displaced from the other rotation center of the pair of rollers as a reference.

  Further, it is preferable that the guide portion supports one of the pair of rollers so as to be displaceable stepwise or steplessly.

  Further, the present invention can be an image forming apparatus employing the transfer paper curl removing apparatus and the image forming apparatus having any of the above-described configurations.

  The transfer paper curl removal apparatus of the present invention can transport the transfer paper after curling has been corrected in the proper direction on the downstream side of the transport path, and even if the curling correction force is increased, the transfer paper is not suitable for the downstream side of the transport path. Can be conveyed in the direction.

  Next, a transfer paper curl removing apparatus and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory view of a multifunction peripheral as an image forming apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory view of a main part of the image forming apparatus according to an embodiment of the present invention, and FIG. FIG. 4 is an explanatory view of a main part of a modified example of the image forming apparatus according to the embodiment of the present invention, and FIG. 5 is an embodiment of the present invention. It is explanatory drawing of the principal part of the curl removal position of the modification of the image forming apparatus which concerns on a form.

(Overall configuration of MFP)
As shown in FIG. 1, a multifunction machine 1 as an image forming apparatus according to an embodiment of the present invention includes a multifunction machine body 2 and a post-processing device body 3 installed adjacent to the multifunction machine body 2. I have.

  The multi-function device main body 2 can use a plurality of transfer paper storage devices 4, 5, 6 that can be pulled out from the front surface, and transfer paper different from the transfer paper storage devices 4, 5, 6. A manual feed tray 7 that can be opened and closed on one side surface of the multifunction machine main body 2, an automatic document feeder (ADF) 8 that is used when reading a document as various functions of a copying machine, a facsimile machine, and a scanner, and a display screen 9 and an operation unit 10 for setting and selecting various functions and the like.

  Note that the shape, configuration, function, and the like of the multifunction machine 1 are not limited to those shown in the drawings.

(Internal structure of MFP main body 2)
In addition, the transfer paper storage devices 4, 5, 6 or the transfer paper (not shown) stored in the manual feed tray 7 are taken out of the multifunction machine main body 2 and disposed on the side surface of the post-processing device 3. A conveyance path 12 that conveys toward the paper tray 11, a registration unit 13 that is disposed on the upstream side in the sheet conveyance direction of the conveyance path 12, and a downstream side in the sheet conveyance direction of the conveyance path 12 relative to the registration unit 13. The image forming unit 14, the fixing unit 15 that fixes the toner image transferred to the surface of the transfer paper by the image forming unit 14 on the surface of the transfer paper, and the most downstream portion in the MFP main body 2 of the transport path 12 The discharge unit 16 is provided.

  Further, a plurality of paths are branched and merged in the conveyance path 12. In the present embodiment, a branch path 17 disposed on the downstream side of the conveyance path 12 in the sheet conveyance direction from the fixing unit 15, and a branch path A plurality of originals set on the ADF 8 and a reverse path 19 for returning the transfer paper guided to 17 to the transport path 12 upstream of the registration unit 13 in the sheet transport direction in a state where the front and back are reversed via the switchback path 18. In this case, a reverse discharge path 20 is provided that guides the discharge surface of the transfer paper after the single-sided printing process to the paper discharge unit 16 in a state where the transfer surface is aligned with the document order.

(Configuration of resist portion 13)
The registration unit 13 includes a registration sensor 21 that detects a leading end of the transfer paper taken out from the transfer paper storage devices 4, 5, and 6 or the manual feed tray 7, and a downstream side of the conveyance path 12 in the sheet conveyance direction from the registration sensor 21. And a pair of registration rollers 22 arranged on the side.

  The registration sensor 21 detects the transfer paper to synchronize the position of the leading edge of the transfer paper and the position of a toner image formed on the surface of the photosensitive drum 23 described later. Rotation of the registration roller pair 22 and the photosensitive drum 23 is started after a lapse of a predetermined time from the detection of the toner image. The rotation drive of the drum 23 is stopped. The registration sensor 21 detects the sheet length along the sheet conveyance direction of the transfer paper sent from the transfer paper storage devices 4, 5, 6 to the conveyance path 12, and after detecting the leading edge of the transfer paper. The length of the transfer paper (direction along the sheet conveyance direction) is detected based on the time until the trailing edge is detected.

  The registration roller pair 22 is connected to a drive source (not shown) such as a motor. Then, in a stationary state, the registration roller pair 22 corrects the oblique feeding of the transfer paper by instantaneously stopping the transfer paper when the leading edge of the transfer paper is nipped.

(Configuration of the image forming unit 14)
The image forming unit 14 includes a photosensitive drum 23, a charging device 24, an exposure device 25, a developing device 26, a transfer device 27, a cleaning device 28, a static elimination device 29, and the like disposed around the photosensitive drum 23. .

  As a result, in the image forming unit 14, the photosensitive drum 23 is rotationally driven at a predetermined process speed (circumferential speed) by a driving unit (not shown), and the surface thereof is uniformly charged to a predetermined polarity and potential by the charging device 24. .

  An electrostatic latent image is formed on the surface of the charged photosensitive drum 23 by the exposure device 25. Here, the exposure device 25 is connected via a communication line such as a print data read by the scanner unit using the ADF 8 by a copying machine function, a print data received through a telephone line by a facsimile function, a network by a printer function, for example. Based on the print data output from a personal computer or the like, the surface of the photosensitive drum 23 is irradiated with laser light, and the charge on the laser light irradiated portion of the surface of the photosensitive drum 23 is removed, and electrostatic according to the image information. A latent image is formed.

  The electrostatic latent image formed on the surface of the photosensitive drum 23 is developed as an untransferred toner image by electrostatically attaching a charged toner to the developing device 26. Further, the untransferred toner image is transferred as an unfixed toner image onto the surface of the transfer paper by the cooperation of the photosensitive drum 23 and the transfer device 27.

  At this time, the photosensitive drum 23 on which the untransferred toner image is transferred to the surface of the transfer paper as an unfixed toner image has the residual toner removed by the cleaning device 28 and at the same time the charge eliminating device for charging at the next image formation. 29 to remove static electricity.

(Configuration of the fixing unit 15)
In order to fix the unfixed toner image transferred to the surface of the transfer paper by the image forming unit 14, the fixing unit 15 fixes a heating roller (or a heating roller) disposed on the surface of the transfer paper, that is, on the unfixed toner image side. Belt) 30 and a pressure roller 31 facing the heating roller 30 with the conveyance path 12 interposed therebetween.

  The unfixed toner image formed on the surface of the transfer paper is melted by directly contacting the heating roller 30, and is melted on the surface of the transfer paper as it is by being pressed by the pressure roller 31 from the back surface side of the transfer paper. The toner is fixed as a fixed image.

  The surface of the heating roller 30 is subjected to a surface coating process or the like so that the molten toner does not adhere. Further, the molten toner or the like adhering to the surface of the heating roller 30 is removed by a cleaning device or the like (not shown).

(Configuration of discharge unit 16)
The discharge unit 16 includes a hard roller 32 made of a relatively hard material (for example, metal) disposed on the surface side of the transfer paper, that is, the fixed image side, and a hard roller 32 across the conveyance path 12. An elastic roller 33 made of an opposed relatively soft material (for example, sponge or rubber), a support shaft 34 that rotatably supports the elastic roller 33, and elastically located at both ends of the support shaft 34 An arcuate guide groove 35 that swings and displaces the roller 33 is provided.

  For example, as shown in FIG. 2, the hard roller 32 and the elastic roller 33 are in a state where the rotation center P1 of the hard roller 32 and the rotation center Q1 of the elastic roller 33 are vertical (when the conveyance direction of the conveyance path 12 is horizontal). The hard roller 32 and the elastic roller 33 are in contact with each other (light pressure contact state) in the vertical state so that the nip portion 36 is formed.

  The hard roller 32 and the elastic roller 33 have a nip portion 36 when it is assumed that no curling has occurred on the transfer paper at the fixing portion 15 when the rotation center P1 and the rotation center Q1 are in a vertical state. When the transfer paper is nip conveyed, the transfer paper is set so as to be conveyed substantially horizontally to the transfer paper discharge port 37 of the multifunction machine main body 2 and the transfer paper supply port 38 of the post-processing device 3.

  The guide groove 35 is formed in a unit (not shown) of the multifunction machine main body 2 and the discharge unit 16, and is based on a center P2 displaced in a substantially horizontal direction toward the transfer paper discharge port 37 with respect to the rotation center P1. It is formed in a circular arc shape.

  As a result, the elastic roller 33 is displaced on the circumference of the hard roller 32 so that the guide groove 35 is retracted from the transfer paper discharge port 37 from a position where the rotation center P1 and the rotation center Q1 are in a vertical state. The support shaft 34 is guided.

  Accordingly, the elastic roller 33 is set so that the hard roller 32 bites in by the elastic force of the elastic roller 33 and the pressurizing force of the nip portion 36 increases at the same time as the elastic roller 33 moves away from the transfer paper discharge port 37 and approaches the conveyance path 12. Has been.

  Then, the transfer paper conveyed to the discharge unit 16 is curled in the opposite direction to the curl generated after the fixing process of the fixing unit 15 by the biting of the hard roller 32 with respect to the elastic roller 33 to cancel out the curl. At the same time, for example, as shown in FIG. 3, the transfer paper is set to be sent out substantially horizontally with respect to the transfer paper discharge port 37 and the transfer paper supply port 38 disposed opposite to the transfer paper discharge port 37. ing.

  The guide portion constituted by the support shaft 34 and the guide groove 35 is unitized (equipmentized) as a whole of the discharge portion 16, and the drive sources of the rollers 32 and 33 are the same as other drive systems. Power is transmitted using the drive source.

  The support shaft 34 can be positioned in any stepless manner with respect to the guide groove 35 by, for example, fixing the support shaft 34 with a screw or the like from the back side of a panel (not shown) in which the guide groove 35 is formed. The guide groove 35 may be configured to be positioned stepwise by providing a step or the like.

  In this case, the number of positioning steps, positions, and the like are sold on the market that can be defined within a certain range of width, such as thin paper, middle opening, thick paper, special thick paper, taking into account the paper thickness of the transfer paper, for example. Positioning can be performed for each thickness according to the type of transfer paper that is present.

  Further, the support shaft 35 is configured to be able to reciprocally swing in the guide groove 35 by being driven by a drive source (not shown) using an electric motor, a solenoid, or the like, and a part of various mode settings and the like on the display screen 9 As described above, a discharge setting (paper thickness setting) mode may be provided, and the support shaft 35 may be automatically displaced by selecting a paper thickness such as the above-described thin paper, middle opening, thick paper, and special thick paper.

  Further, as shown in FIGS. 4 and 5, the guide groove 35 is formed in an arc shape with the rotation center P <b> 1 of the hard roller 32 as a reference, and the biting amount with respect to the hard roller 32 is the same at any position, and the feed from the nip portion 36 is performed. A configuration in which only the direction is controlled is also possible.

  As described above, in the transfer paper curl removing apparatus of the present invention, the curl of the transfer paper curled by the fixing unit 15 is removed (offset) by the press contact between the hard roller 32 and the elastic roller 33 having different hardnesses, and the transfer paper curl is transferred. The paper can be transported in a state in which the paper feed (discharge) direction is defined in an appropriate direction toward the transfer paper discharge port 37.

  Further, by increasing the amount of biting in accordance with the amount of displacement of the elastic roller 33, it is possible to increase the curl correction force and transport in the proper direction downstream of the transport path.

  In the above embodiment, the transfer paper curl removing apparatus according to the present invention is applied to the multifunction machine 1 as an image forming apparatus. However, for example, an image forming apparatus in general such as a printer dedicated machine or a copying dedicated machine. Of course, it can be applied to.

  At this time, if the function as a decurling device is required, the device can be arranged without being limited to the discharge unit 15 described above.

  In the above-described embodiment, the elastic roller 33 is displaced in the direction away from the transfer paper discharge port 37 with respect to the hard roller 32. However, the hard roller 32 is discharged with respect to the elastic roller 33. You may displace in the direction approaching the exit 37, and you may displace both the hard roller 32 and the elastic roller 33 in the direction mentioned above, respectively. At this time, it is preferable that the amount of biting of each of the rollers 32 and 33 is variable in any case.

1 is an explanatory diagram of a multifunction peripheral as an image forming apparatus according to an embodiment of the present disclosure. 1 is an explanatory diagram of a main part of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is an explanatory diagram of a main part of a curl removal position of the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing of the principal part of the modification of the image forming apparatus which concerns on one Embodiment of this invention. It is explanatory drawing of the principal part of the curl removal position of the modification of the image forming apparatus which concerns on one Embodiment of this invention. It is explanatory drawing of the principal part of the conventional curl removal position.

Explanation of symbols

1 ... Multifunction machine (image forming device)
2 ... MFP main body 3 ... Post-processing device 16 ... Discharge unit (transfer paper curl removal device)
32. Hard roller (a pair of rollers)
33. Elastic roller (a pair of rollers)
34 ... Support shaft (guide part)
35 ... Guide groove

Claims (6)

  A transfer comprising: a pair of rollers that are opposed to each other in pressure contact and have different hardnesses; and a guide portion that supports at least one of the pair of rollers so as to be displaceable on the other circumference. Paper curl removal device.   The transfer paper curl removing apparatus according to claim 1, wherein the guide portion supports one of the pair of rollers so as to be displaceable stepwise or steplessly.   The guide portion includes an arcuate guide groove based on a center displaced from the other rotation center of the pair of roller pairs so that one of the pair of roller pairs approaches and separates from the other. The transfer paper curl removing apparatus according to claim 1, wherein the transfer paper curl removing apparatus is provided.   The transfer paper curl according to claim 1, wherein the guide portion includes an arcuate guide groove based on a center coaxial with the other rotation center of the pair of rollers. Removal device.   The operation unit for designating one support position of the pair of roller pairs, and a drive unit for displacing one of the pair of roller pairs to a position designated by the operation unit. The transfer paper decurling device according to claim 1.   An image forming apparatus comprising the transfer paper curl removing apparatus according to claim 1.

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